1. Field of the Invention
This invention relates to a method for regulating the natural growth or development of plants by means of chemical treatment. As employed herein, the term "natural growth or development" designates the normal life cycle of the plant in accordance with its genetics and its environment, in the absence of artifical, external influences. More particularly, this invention is concerned with a method wherein turfgrasses are treated with a chemical substance which serves to retard or reduce the rate of turfgrass growth.
2. Description of the Prior Art
U.S. Pat. No. 4,178,167 describes the use of compounds of this invention as herbicides in a procedure for inhibiting or destroying unwanted plants. It should be understood, however, that the regulation of natural growth or development discussed herein does not include herbicidal or killing action, and that the turfgrasses treated in accordance herewith are not unwanted plants.
Although lethal amounts of the materials disclosed herein might be employed to obtain destruction or total inhibition of certain plants, it is contemplated here to employ only such amounts of said materials as will serve to effectively regulate the natural growth or development in the desired manner. As long understood and well recognized by those skilled in the art, such effective plant regulating amounts will vary, not only with the particular material selected for treatment, but also with the regulatory effect to be achieved, the species of plant being treated and its stage of development, and whether a permanent or transient regulating effect is sought. Other factors which may bear upon the determination of an effective plant regulating amount include the plant growth medium, the manner in which the treatment is to be applied, and weather conditions such as temperature and rainfall.
The term "turfgrass" is generally considered as encompassing a variety of specialized grasses which are employed in the development and/or management of certain areas for specific purposes, such as utility, beautification and recreation. The use of a chemical treatment to reduce or retard the natural growth or development of turfgrass provides many advantages. Among the areas in which turfgrasses are most frequently used are roadbanks and medians which parallel long stretches of our highway system, the large grassy areas of golf courses and parks, the grounds which surround large educational or industrial institutions and, of course, the lawn of the homeowner. In all of such areas, it is readily apparent that a chemical treatment which serves to reduce or retard the rate of grass growth is highly desirable since it will serve to minimize the time and costs expended on maintenance. Such a treatment will also provide enchanced appearance by promoting more grass height uniformity and by suppressing unsightly seedhead development.
Growth retarding chemicals have been applied to turf since maleic hydrazide was introduced in 1949. Unfortunately, discoloration and thinning of turf often has accompanied growth suppression. Consequently, the use of retardant chemicals has largely been restricted to roadside and hazardous-to-mow areas. Chemicals with less phytotoxicity are necessary if the full potential of chemical growth retardation in turfgrass management is to be realized. Therefore, it is a particular object of the invention to provide a method of retarding the growth of turfgrass effectively without causing undesired discoloration or thinning of the turf.